1. Field of the Invention
This invention relates to an inspection method and apparatus for enclosed spaces and more particularly, to an interior inspection apparatus and method for tanks and vessels, such as on rail cars, and other enclosed spaces.
2. Description of the Prior Art
A significant problem exists in industry for satisfactorily inspecting enclosed internal spaces that transport or store a multitude of different chemicals, petroleum products, and other substances. Many liquids stored in a tank or vessel may be toxic and corrosive, and can be hazardous to humans. Prior to introducing these substances into a vessel or tank, it is desirable to inspect the interior of the tank or vessel to evaluate its suitability for continued use and determine whether repairs or other servicing is required for safe storage and/or transport of the substances. Such inspections are needed to consider numerous conditions within the vessel or tank prior to cleaning, repairing, or filling. The vessel or tank should be inspected for overall quality assurance of the structure and verify the level of corrosion and the like within the interior. During these inspections, the physical integrity of the lining of the tank can be evaluated as well as the status of any coils or other appurtenances that may be present within the confined space.
In many cases, it is necessary to make a residue measurement prior to cleaning or filling the vessel and otherwise generally inspect the enclosed space for safe pre-cleaning. This inspection of the interior of tanks or hoppers is particularly necessary for safe operation of rail cars which transport a host of chemicals and other products that can be hazardous to humans or the environment, if not safely contained within the rail car.
Because of the size and configurations of large vessels or tanks in the field, it is extremely difficult to gain access to the interior of the enclosed space for an adequate inspection. In addition, it can be unsafe for an individual to enter into the enclosed space even when access is possible, due to the potentially dangerous nature of the materials that were stored or transported in the vessel or tank.
In the past, internal inspections have been made either by physical entry or by various types of optical equipment, such as periscopes and the like. Such known techniques of visualizing the condition of an enclosed space are not optimumly satisfactory in providing an inspector with a complete visualization of the condition of the interior and are not capable of providing a permanent visual and audio record for later reference. The attainment of effective visualization of the interior of a vessel a tank, or any other confined space is an important need in the industry for reasons of economy, safety, sustained service of the equipment, and proper subsequent handling of materials being transported or stored. Accordingly, it is desirable in the prior art to provide an improved visual inspection method and apparatus for effectively viewing and evaluating the physical condition of the interior of a confined space.